In the public domain, ideas undergird the specific policy decisions that elected officials and administrators make in order to achieve the shared goals their communities and constituencies articulate. Ideas are the pistons that drive the engines of change. The study of change, moreover, is a study of our ambivalence toward it. On the one hand, we embrace it with some assumption of its inevitable desirability, equating it with progress, with our aspirations for social improvement, with our propensity for wanting society to be better off, though what better off means often remains unclear and inchoate. Public figures routinely offer us a vision of the future that consists of little more than earnestly delivered promises to get this country...